Backport xtensa_codegen to main (v2)

Makefile

@@ -454,6 +454,7 @@ SOURCE_FILES = \
   CodeGen_WebAssembly.cpp \
   CodeGen_WebGPU_Dev.cpp \
   CodeGen_X86.cpp \
+  CodeGen_Xtensa.cpp \
   CompilerLogger.cpp \
   ConstantBounds.cpp \
   ConstantInterval.cpp \
@@ -492,6 +493,7 @@ SOURCE_FILES = \
   HexagonOptimize.cpp \
   ImageParam.cpp \
   InferArguments.cpp \
+  InjectDmaTransfer.cpp \
   InjectHostDevBufferCopies.cpp \
   Inline.cpp \
   InlineReductions.cpp \
@@ -596,11 +598,14 @@ SOURCE_FILES = \
   Var.cpp \
   VectorizeLoops.cpp \
   WasmExecutor.cpp \
-  WrapCalls.cpp
+  WrapCalls.cpp \
+  XtensaOptimize.cpp
 
  C_TEMPLATE_FILES = \
    CodeGen_C_prologue \
-   CodeGen_C_vectors
+   CodeGen_C_vectors \
+   CodeGen_Xtensa_prologue \
+   CodeGen_Xtensa_vectors
 
 HTML_TEMPLATE_FILES = \
    StmtToHTML_dependencies.html \
@@ -648,6 +653,7 @@ HEADER_FILES = \
   CodeGen_PyTorch.h \
   CodeGen_Targets.h \
   CodeGen_WebGPU_Dev.h \
+  CodeGen_Xtensa.h \
   CompilerLogger.h \
   ConciseCasts.h \
   CPlusPlusMangle.h \
@@ -692,6 +698,7 @@ HEADER_FILES = \
   HexagonOptimize.h \
   ImageParam.h \
   InferArguments.h \
+  InjectDmaTransfer.h \
   InjectHostDevBufferCopies.h \
   Inline.h \
   InlineReductions.h \
@@ -780,7 +787,8 @@ HEADER_FILES = \
   Util.h \
   Var.h \
   VectorizeLoops.h \
-  WrapCalls.h
+  WrapCalls.h \
+  XtensaOptimize.h
 
 OBJECTS = $(SOURCE_FILES:%.cpp=$(BUILD_DIR)/%.o)
 HEADERS = $(HEADER_FILES:%.h=$(SRC_DIR)/%.h)
@@ -1241,6 +1249,10 @@ clean:
 	rm -rf $(DISTRIB_DIR)
 	rm -rf $(ROOT_DIR)/apps/*/bin
 
+.PHONY: clean_xtensa
+clean_xtensa:
+	rm -rf $(XTENSA_RUNTIME_OBJS) $(DISTRIB_DIR)/lib/libHalideRuntime-xtensa.a
+
 CORRECTNESS_TESTS = $(shell ls $(ROOT_DIR)/test/correctness/*.cpp) $(shell ls $(ROOT_DIR)/test/correctness/*.c)
 PERFORMANCE_TESTS = $(shell ls $(ROOT_DIR)/test/performance/*.cpp)
 ERROR_TESTS = $(shell ls $(ROOT_DIR)/test/error/*.cpp)
@@ -1273,6 +1285,7 @@ test_correctness_multi_gpu: correctness_gpu_multi_device
 # 3) Externally-written JIT-based tests
 GENERATOR_AOT_TESTS = $(GENERATOR_EXTERNAL_TESTS:$(ROOT_DIR)/test/generator/%_aottest.cpp=generator_aot_%)
 GENERATOR_AOTCPP_TESTS = $(GENERATOR_EXTERNAL_TESTS:$(ROOT_DIR)/test/generator/%_aottest.cpp=generator_aotcpp_%)
+GENERATOR_AOTXTENSA_TESTS = $(GENERATOR_EXTERNAL_TESTS:$(ROOT_DIR)/test/generator/%_aottest.cpp=generator_aotcpp_xtensa_%)
 GENERATOR_JIT_TESTS = $(GENERATOR_EXTERNAL_TESTS:$(ROOT_DIR)/test/generator/%_jittest.cpp=generator_jit_%)
 
 # multitarget test doesn't make any sense for the CPP backend; just skip it.
@@ -1303,6 +1316,62 @@ GENERATOR_AOTCPP_TESTS := $(filter-out generator_aotcpp_gpu_multi_context_thread
 
 test_aotcpp_generator: $(GENERATOR_AOTCPP_TESTS)
 
+# Tests below probably don't make much sense for Xtensa.
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_alias,$(GENERATOR_AOTXTENSA_TESTS))
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_async_parallel,$(GENERATOR_AOTXTENSA_TESTS))
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_autograd,$(GENERATOR_AOTXTENSA_TESTS))
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_cxx_mangling,$(GENERATOR_AOTXTENSA_TESTS))
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_cxx_mangling_define_extern,$(GENERATOR_AOTXTENSA_TESTS))
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_metadata_tester,$(GENERATOR_AOTXTENSA_TESTS))
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_string_param,$(GENERATOR_AOTXTENSA_TESTS))
+
+# Tests below work, but need to disable parallel in the schedule.
+# TODO(vksnk): figure out what's wrong with parallel in this case.
+# https://github.com/halide/Halide/issues/7856
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_example,$(GENERATOR_AOTXTENSA_TESTS))
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_mandelbrot,$(GENERATOR_AOTXTENSA_TESTS))
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_pyramid,$(GENERATOR_AOTXTENSA_TESTS))
+
+# Xtensa doesn't have float64 vectors
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_templated,$(GENERATOR_AOTXTENSA_TESTS))
+
+# Needs define_extent
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_tiled_blur,$(GENERATOR_AOTXTENSA_TESTS))
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_nested_externs,$(GENERATOR_AOTXTENSA_TESTS))
+
+# Segmentation fault, tests provide custom runtime and user context.
+# https://github.com/halide/Halide/issues/7857
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_user_context,$(GENERATOR_AOTXTENSA_TESTS))
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_user_context_insanity,$(GENERATOR_AOTXTENSA_TESTS))
+
+# multitarget test doesn't make any sense for the Xtensa backend; just skip it.
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_multitarget,$(GENERATOR_AOTXTENSA_TESTS))
+
+# Note that many of the AOT-CPP tests are broken right now;
+# remove AOT-CPP tests that don't (yet) work for C++ backend
+# (each tagged with the *known* blocking issue(s))
+
+# sanitizercoverage relies on LLVM-specific hooks, so it will never work with the C backend
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_sanitizercoverage,$(GENERATOR_AOTXTENSA_TESTS))
+
+# https://github.com/halide/Halide/issues/2084 (only if opencl enabled))
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_cleanup_on_error,$(GENERATOR_AOTXTENSA_TESTS))
+
+# https://github.com/halide/Halide/issues/7273
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_msan,$(GENERATOR_AOTXTENSA_TESTS))
+
+# https://github.com/halide/Halide/issues/7272
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_memory_profiler_mandelbrot,$(GENERATOR_AOTXTENSA_TESTS))
+
+# https://github.com/halide/Halide/issues/4916
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_stubtest,$(GENERATOR_AOTXTENSA_TESTS))
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_stubuser,$(GENERATOR_AOTXTENSA_TESTS))
+
+# Build requirements are finicky, testing non-C++ backend is good enough here
+GENERATOR_AOTXTENSA_TESTS := $(filter-out generator_aotcpp_xtensa_gpu_multi_context_threaded,$(GENERATOR_AOTXTENSA_TESTS))
+
+test_aotcpp_xtensa_generator: $(GENERATOR_AOTXTENSA_TESTS)
+
 # This is just a test to ensure than RunGen builds and links for a critical mass of Generators;
 # not all will work directly (e.g. due to missing define_externs at link time), so we disable
 # those known to be broken for plausible reasons.
@@ -1487,6 +1556,7 @@ $(BIN_DIR)/%.generator: $(BUILD_DIR)/GenGen.o $(TEST_DEPS) $(BUILD_DIR)/%_genera
 NAME_MANGLING_TARGET=$(NON_EMPTY_TARGET)-c_plus_plus_name_mangling
 
 GEN_AOT_OUTPUTS=-e static_library,c_header,c_source,registration
+GEN_AOT_XTENSA_OUTPUTS=-e c_source
 
 # By default, %.a/.h are produced by executing %.generator. Runtimes are not included in these.
 # (We explicitly also generate .cpp output here as well, as additional test surface for the C++ backend.)
@@ -1518,6 +1588,14 @@ $(FILTERS_DIR)/cxx_mangling.a: $(BIN_DIR)/cxx_mangling.generator $(FILTERS_DIR)/
 	$(CURDIR)/$< -g cxx_mangling $(GEN_AOT_OUTPUTS),function_info_header -o $(CURDIR)/$(FILTERS_DIR) target=$(TARGET)-no_runtime-c_plus_plus_name_mangling -f "HalideTest::AnotherNamespace::cxx_mangling"
 	$(ROOT_DIR)/tools/makelib.sh $@ $@ $(FILTERS_DIR)/cxx_mangling_externs.o
 
+$(FILTERS_DIR)/pyramid_xtensa.halide_generated.cpp: $(BIN_DIR)/pyramid.generator
+	@mkdir -p $(@D)
+	$(CURDIR)/$< -g pyramid $(GEN_AOT_XTENSA_OUTPUTS) -o $(CURDIR)/$(FILTERS_DIR) target=xtensa-32-noos-no_runtime -n pyramid_xtensa levels=10
+
+$(FILTERS_DIR)/%_xtensa.halide_generated.cpp: $(BIN_DIR)/%.generator
+	@mkdir -p $(@D)
+	$(CURDIR)/$< -g $* $(GEN_AOT_XTENSA_OUTPUTS) -o $(CURDIR)/$(FILTERS_DIR) target=xtensa-32-noos-no_runtime -n $*_xtensa
+
 ifneq ($(TEST_CUDA), )
 # Also build with a gpu target to ensure that the GPU-Host generation
 # code handles name mangling properly. (Note that we don't need to
@@ -1729,6 +1807,11 @@ $(BIN_DIR)/$(TARGET)/generator_aotcpp_%: $(ROOT_DIR)/test/generator/%_aottest.cp
 	@mkdir -p $(@D)
 	$(CXX) $(GEN_AOT_CXX_FLAGS) $(filter %.cpp %.o %.a,$^) $(OPTIMIZE) $(GEN_AOT_INCLUDES) $(GEN_AOT_LD_FLAGS) -o $@
 
+# Also make AOT testing targets that depends on the .cpp output (rather than .a).
+$(BIN_DIR)/$(TARGET)/generator_aotcpp_xtensa_%: $(ROOT_DIR)/test/generator/%_aottest.cpp $(FILTERS_DIR)/%_xtensa.halide_generated.cpp $(FILTERS_DIR)/%.h $(RUNTIME_EXPORTED_INCLUDES) $(BIN_DIR)/$(TARGET)/runtime.a
+	@mkdir -p $(@D)
+	clang++ $(GEN_AOT_CXX_FLAGS) $(filter %.cpp %.o %.a,$^) $(OPTIMIZE) $(GEN_AOT_INCLUDES) $(GEN_AOT_LD_FLAGS) -Wno-error -I$(CSTUB_INCLUDE_PATH) -L$(CSTUB_LIB_PATH) -lcstub -D XCHAL_VISION_TYPE=7 -D XCHAL_VISION_SIMD16=32 -D XCHAL_DATA_WIDTH=64 -o $@
+
 # MSAN test doesn't use the standard runtime
 $(BIN_DIR)/$(TARGET)/generator_aot_msan: $(ROOT_DIR)/test/generator/msan_aottest.cpp $(FILTERS_DIR)/msan.a $(FILTERS_DIR)/msan.h $(RUNTIME_EXPORTED_INCLUDES)
 	@mkdir -p $(@D)
@@ -2073,6 +2156,11 @@ generator_aotcpp_%: $(BIN_DIR)/$(TARGET)/generator_aotcpp_%
 	cd $(TMP_DIR) ; $(CURDIR)/$<
 	@-echo
 
+generator_aotcpp_xtensa_%: $(BIN_DIR)/$(TARGET)/generator_aotcpp_xtensa_%
+	@-mkdir -p $(TMP_DIR)
+	cd $(TMP_DIR) ; $(CURDIR)/$<
+	@-echo
+
 $(TMP_DIR)/images/%.png: $(ROOT_DIR)/tutorial/images/%.png
 	@-mkdir -p $(TMP_DIR)/images
 	cp $< $(TMP_DIR)/images/
@@ -2506,6 +2594,27 @@ $(DISTRIB_DIR)/bin/get_host_target
 .PHONY: distrib
 distrib: $(DISTRIB_DIR)/lib/libHalide.$(SHARED_EXT) autoschedulers
 
+XTENSA_RUNTIME_SRC=$(ROOT_DIR)/src/runtime/alignment_128.cpp \
+                   $(ROOT_DIR)/src/runtime/errors.cpp \
+                   $(ROOT_DIR)/src/runtime/posix_error_handler.cpp \
+                   $(ROOT_DIR)/src/runtime/msan_stubs.cpp \
+                   $(ROOT_DIR)/src/runtime/to_string.cpp \
+                   $(ROOT_DIR)/src/runtime/posix_print.cpp \
+                   $(ROOT_DIR)/src/runtime/posix_io.cpp \
+                   $(ROOT_DIR)/src/runtime/posix_aligned_alloc.cpp \
+                   $(ROOT_DIR)/src/runtime/posix_allocator.cpp \
+                   $(ROOT_DIR)/src/runtime/xtensa_dma.cpp \
+
+XTENSA_RUNTIME_OBJS=$(patsubst $(ROOT_DIR)/src/runtime/%,$(BIN_DIR)/%,$(patsubst %.cpp,%.o,$(XTENSA_RUNTIME_SRC)))
+
+$(XTENSA_RUNTIME_OBJS): $(BIN_DIR)/%.o: $(ROOT_DIR)/src/runtime/%.cpp
+	xt-clang++ -O2 -mlongcalls -c -std=c++17 -stdlib=libc++ -D COMPILING_HALIDE_RUNTIME -DBITS_32 -ffreestanding $< -o $@
+
+$(DISTRIB_DIR)/lib/libHalideRuntime-xtensa.a: $(XTENSA_RUNTIME_OBJS)
+	xt-ar rcs $@ $^
+
+xtensa-runtime: distrib $(DISTRIB_DIR)/lib/libHalideRuntime-xtensa.a
+
 $(DISTRIB_DIR)/halide.tgz: distrib
 	ln -sf $(DISTRIB_DIR) halide
 	tar -czf $(BUILD_DIR)/halide.tgz \

apps/simd_op_check/Makefile

@@ -1,10 +1,13 @@
 include ../support/Makefile.inc
 
 CXX-hexagon-32-noos-hvx_128 ?= $(HL_HEXAGON_TOOLS)/bin/hexagon-clang++
+CXX-xtensa ?= clang++
 
 CXXFLAGS-hexagon-32-noos-hvx_128 ?= -mhvx -mhvx-length=128B -G0
+CXXFLAGS-xtensa ?= -std=c++17 -I$(CSTUB_INCLUDE_PATH) -D XCHAL_VISION_TYPE=7 -D XCHAL_VISION_SIMD16=32 -D XCHAL_DATA_WIDTH=64
 
 LDFLAGS-hexagon-32-noos-hvx_128 ?= -L../../src/runtime/hexagon_remote/bin/v60/ -lsim_qurt
+LDFLAGS-xtensa ?= -lpthread -ldl
 
 all: \
 	$(BIN)/driver-host \
@@ -18,6 +21,7 @@ arm_32: $(BIN)/driver-arm-32-android
 arm_64: $(BIN)/driver-arm-64-android
 
 host: $(BIN)/driver-host
+xtensa: $(BIN)/driver-xtensa
 
 $(BIN)/hexagon-32-noos-%/filters.h:
 	@mkdir -p $(@D)
@@ -28,6 +32,15 @@ $(BIN)/hexagon-32-noos-%/filters.h:
 	cd $(BIN)/hexagon-32-noos-$*; for f in test_*.h; do n=$${f/.h/}; echo '{"'$${n}'", &'$${n}'},'; done >> filters.h
 	echo '{NULL, NULL}};' >> $(BIN)/hexagon-32-noos-$*/filters.h
 
+$(BIN)/xtensa/filters.h:
+	@mkdir -p $(@D)
+	make -C ../../ bin/correctness_simd_op_check_xtensa
+	cd $(BIN)/xtensa && HL_TARGET=xtensa-32-noos LD_LIBRARY_PATH=../../../../bin:$$LD_LIBRARY_PATH ../../../../bin/correctness_simd_op_check_xtensa
+	cat $(BIN)/xtensa/test_*.h > $(BIN)/xtensa/filter_headers.h
+	echo "filter filters[] = {" > $(BIN)/xtensa/filters.h
+	cd $(BIN)/xtensa; for f in test_*.h; do n=$${f/.h/}; echo '{"'$${n}'", &'$${n}'},'; done >> filters.h
+	echo '{NULL, NULL}};' >> $(BIN)/xtensa/filters.h
+
 $(BIN)/%/filters.h:
 	@mkdir -p $(@D)
 	make -C ../../ bin/correctness_simd_op_check
@@ -41,5 +54,9 @@ $(BIN)/driver-%: driver.cpp $(BIN)/%/filters.h
 	@mkdir -p $(@D)
 	$(CXX-$*) $(CXXFLAGS-$*) -I ../../include $(OPTIMIZE) -I $(BIN)/$* driver.cpp $(BIN)/$*/test_*.o $(BIN)/$*/simd_op_check_runtime.o -o $@ $(LDFLAGS-$*) $(HALIDE_SYSTEM_LIBS)
 
+$(BIN)/driver-xtensa: driver.cpp $(BIN)/xtensa/filters.h
+	@mkdir -p $(@D)
+	$(CXX-xtensa) $(CXXFLAGS-xtensa) -I ../../include $(OPTIMIZE) -I $(BIN)/xtensa driver.cpp $(BIN)/xtensa/test_*.cpp $(BIN)/xtensa/simd_op_check_runtime.o $(CSTUB_LIB_PATH)/libcstub.a -o $@ $(LDFLAGS-xtensa) $(HALIDE_SYSTEM_LIBS)
+
 clean:
 	rm -rf $(BIN)

python_bindings/src/halide/halide_/PyEnums.cpp

@@ -93,7 +93,8 @@ void define_enums(py::module &m) {
         .value("Hexagon", Target::Arch::Hexagon)
         .value("POWERPC", Target::Arch::POWERPC)
         .value("RISCV", Target::Arch::RISCV)
-        .value("WebAssembly", Target::Arch::WebAssembly);
+        .value("WebAssembly", Target::Arch::WebAssembly)
+        .value("Xtensa", Target::Arch::Xtensa);
 
     // Please keep sorted.
     py::enum_<Target::Processor>(m, "TargetProcessorTune")
@@ -177,6 +178,7 @@ void define_enums(py::module &m) {
         .value("SVE2", Target::Feature::SVE2)
         .value("ARMDotProd", Target::Feature::ARMDotProd)
         .value("ARMFp16", Target::Feature::ARMFp16)
+        .value("XtensaQ8", Target::Feature::XtensaQ8)
         .value("LLVMLargeCodeModel", Target::Feature::LLVMLargeCodeModel)
         .value("RVV", Target::Feature::RVV)
         .value("ARMv8a", Target::Feature::ARMv8a)

python_bindings/src/halide/halide_/PyFunc.cpp

@@ -420,6 +420,8 @@ void define_func(py::module &m) {
 
             .def("infer_arguments", &Func::infer_arguments)
 
+            .def("dma", (Func & (Func::*)()) & Func::dma)
+
             .def("__repr__", [](const Func &func) -> std::string {
                 std::ostringstream o;
                 o << "<halide.Func '" << func.name() << "'>";

src/AssociativeOpsTable.cpp

@@ -20,12 +20,14 @@ enum class ValType {
     UInt64 = 4,
     Int8 = 5,
     Int16 = 6,
-    Int32 = 7,
-    Int64 = 8,
-    Float16 = 9,
-    Float32 = 10,
-    Float64 = 11,
-    All = 12,  // General type (including all previous types)
+    Int24 = 7,
+    Int32 = 8,
+    Int48 = 9,
+    Int64 = 10,
+    Float16 = 11,
+    Float32 = 12,
+    Float64 = 13,
+    All = 14,  // General type (including all previous types)
 };
 
 ValType convert_halide_type_to_val_type(const Type &halide_t) {
@@ -50,8 +52,12 @@ ValType convert_halide_type_to_val_type(const Type &halide_t) {
             val_t = ValType::Int8;
         } else if (halide_t.bits() == 16) {
             val_t = ValType::Int16;
+        } else if (halide_t.bits() == 24) {
+            val_t = ValType::Int24;
         } else if (halide_t.bits() == 32) {
             val_t = ValType::Int32;
+        } else if (halide_t.bits() == 48) {
+            val_t = ValType::Int48;
         } else {
             internal_assert(halide_t.bits() == 64);
             val_t = ValType::Int64;

src/CMakeLists.txt

@@ -84,6 +84,7 @@ target_sources(
     CodeGen_Targets.h
     CodeGen_Vulkan_Dev.h
     CodeGen_WebGPU_Dev.h
+    CodeGen_Xtensa.h
     CompilerLogger.h
     ConciseCasts.h
     CPlusPlusMangle.h
@@ -128,6 +129,7 @@ target_sources(
     HexagonOptimize.h
     ImageParam.h
     InferArguments.h
+    InjectDmaTransfer.h
     InjectHostDevBufferCopies.h
     Inline.h
     InlineReductions.h
@@ -217,6 +219,7 @@ target_sources(
     VectorizeLoops.h
     WasmExecutor.h
     WrapCalls.h
+    XtensaOptimize.h
 )
 
 # The sources that go into libHalide. For the sake of IDE support, headers that
@@ -265,6 +268,7 @@ target_sources(
     CodeGen_WebAssembly.cpp
     CodeGen_WebGPU_Dev.cpp
     CodeGen_X86.cpp
+    CodeGen_Xtensa.cpp
     CompilerLogger.cpp
     CPlusPlusMangle.cpp
     ConstantBounds.cpp
@@ -303,6 +307,7 @@ target_sources(
     HexagonOptimize.cpp
     ImageParam.cpp
     InferArguments.cpp
+    InjectDmaTransfer.cpp
     InjectHostDevBufferCopies.cpp
     Inline.cpp
     InlineReductions.cpp
@@ -409,11 +414,14 @@ target_sources(
     VectorizeLoops.cpp
     WasmExecutor.cpp
     WrapCalls.cpp
+    XtensaOptimize.cpp
 )
 
 set(C_TEMPLATE_FILES
     CodeGen_C_prologue
     CodeGen_C_vectors
+    CodeGen_Xtensa_prologue
+    CodeGen_Xtensa_vectors
 )
 
 set(HTML_TEMPLATE_FILES

src/CodeGen_C.h

@@ -86,7 +86,7 @@ class CodeGen_C : public IRPrinter {
     std::string id;
 
     /** The target being generated for. */
-    Target target;
+    const Target target;
 
     /** Controls whether this instance is generating declarations or
      * definitions and whether the interface us extern "C" or C++. */
@@ -300,7 +300,7 @@ class CodeGen_C : public IRPrinter {
     void emit_constexpr_function_info(const std::string &function_name,
                                       const std::vector<LoweredArgument> &args,
                                       const MetadataNameMap &metadata_name_map);
-    void emit_halide_free_helper(const std::string &alloc_name, const std::string &free_function);
+    virtual void emit_halide_free_helper(const std::string &alloc_name, const std::string &free_function);
 };
 
 }  // namespace Internal